Life Science
Bacteria: The Good, The Bad and
The Ugly
Brief Review
Bacterial Shapes: COCCI
Sphere-shaped bacteria
(cocci) sometimes grow in
chains or in clumps like a
bunch of grapes.
Streptococcus
(strep throat)
Staphylococci
(responsible for
"staph" infections and
gangrene)
Bacterial Shape: BACILLUS
Rod-shaped bacteria (bacilli)
can also form in chains. Some
types of these bacteria also
have whiplike structures called
flagella to help them move
around.
Escherichia coli or E.coli
(found in the intestines of
mammals)
Salmonella typhi
(causes typhoid fever and
food poisoning)
Bacterial Shape: SPIRILLA
Spiral-shaped bacteria
(spirilla) can use their
shape to propel
themselves by twisting
like a corkscrew.
Treponema
pallidumcholera
(syphilis)
Borrelia
burgdorferi (Lyme
disease)
THE GOOD:
Not all bacteria are harmful.
• Bacteria as decomposers
Underside of a leaf
enlarged 5000x
Nitrogen Fixing Bacteria
• Some bacteria have the
ability to absorb nitrogen
and change it into a form
usable by plants
• We eat the plants or the
animals that ate the plants
and we get that nitrogen
alfalfa
• Plants such as clover, peas,
beans -legumes
Fermentation- the breakdown of some
nutrient molecule(usually sugar) into alcohol or
some other food molecule such as:
• Wine and cider are turned into vinegar
• Sauerkraut from cabbage
• Pickles from cucumber
• Silage from corn
• Linen from flax
• Dairy products-yogurt, cheese,
• Cottage cheese from sour milk
• Holes in Swiss cheese from gases
generated by bacteria
THE BAD:
Pathogenic bacteria-disease causing
• Food poisoning-
botulism
• Halitosis
• Tooth decay
• anthrax
www.dmacc.cc.ia.us/instructors/scottie.htm
The UGLY
What bacteria can do….
Corn blight
Tooth
decay
Rash of
anthrax
lyme disease
Your Assignment:
Research AND powerpoint presentation
• Choose one GOOD and one BAD bacteria
• GOOD
– how product is made and how bacteria are involved
• BAD
– what disease How is infection spread
– Symptoms picture /scientific name
– Treatment where bacteria is found